â€œIn the old days, we used to be called newsletter publishers,â€? says Om Malik, a technology writer who quit his job at Business 2.0 magazine in June to work full-time on his blog, GigaOm. He has hired two other writers, and his blog now attracts about 50,000 readers a day, generating â€œtens of thousandsâ€? in monthly revenues. Costs, including salaries, are around $20,000 a month.